U.S. Pat. No. 4,714,051, assigned to the assignee of the present invention, discloses a stored chemical energy power propulsion system having a reactor having a closed chamber in which lithium in the form of a body of lithium metal shot encapsulated in a thin layer of predominantly fluorine substituted polyolefin based polymeric material is reacted within the chamber with a gaseous oxidant such as SF.sub.6. An exothermic reaction is initiated when the aforementioned lithium shot is melted in the presence of gaseous SF.sub.6 which is introduced into the closed chamber via an inlet port. An initiator supplies sufficient thermal energy to the metallic lithium within the chamber to melt the encapsulated lithium which reacts initially with the polymeric material and thereafter in a highly exothermic manner to generate heat upon reaction with the SF.sub.6. A heat exchanger, which is part of the chamber walls, converts water which is pumped to an inlet of the heat exchanger into superheated steam which is used for supplying propulsive power to a vehicle such as a torpedo. This system has approximately 75-80% of the volume of the chamber initially charged with the encapsulated lithium. The remainder of the volume contains the initiator and ullage to allow for temporary expansion of the fuel at the start of the reaction. The reaction has short pressure peak above ambient pressure followed by a highly exothermic reaction having pressures within the chamber below the ambient pressure. As the reaction is ongoing, the ullage within the chamber is occupied by a low pressure fuel vapor with solid reaction products being contained within the liquid metal.
While the foregoing system produces a high power output useful for the propelling of a vehicle such as a torpedo, the chemical reaction can cause damage or failure in the chamber walls when the attitude of the chamber rapidly changes consequent from vehicular motion or is varied substantially from a horizontal plane. Rapid changes in attitude or altitudes substantially varied from the horizontal plane cause the gaseous oxidant inside the chamber to move about the chamber and directly contact the chamber wall(s) and end plate including inlet port(s) for introducing the gaseous oxidant which is introduced into the reactor chamber at a metered rate to sustain the exothermic chemical reaction. When the interior of the chamber is directly exposed to the gaseous oxidant, an increase in the pressure occurs within the chamber and further the direct contact of the gaseous oxidant can corrode the interior wall(s) thereof or the inlet port(s) because the gaseous oxidant does not react sufficiently with the liquid lithium. The effects of these two occurrences can cause the chamber to rupture and fail.